Insulating

ABSTRACT

Thermal insulation comprising a boundary comprising a first boundary section, a second boundary section and a third boundary section which connects the first and second boundary sections together; and an internal insulating region inside the boundary and configured to thermally insulate the first boundary section from the second boundary section; wherein the third boundary section follows an indirect path between the first and second boundary sections. An apparatus configured to volatilize components of smokable material, comprising the insulation, is also described.

FIELD

The invention relates to insulating.

BACKGROUND

Smoking articles such as cigarettes and cigars burn tobacco during useto create tobacco smoke. Attempts have been made to provide alternativesto these smoking articles by creating products which release compoundswithout creating tobacco smoke. Examples of such products are so-calledheat-not-burn products which release compounds by heating, but notburning, tobacco.

The invention aims to provide an improved apparatus and method forheating tobacco, which can be used in a heat-not-burn device.

SUMMARY

According to the invention, there is provided thermal insulationcomprising:

-   -   a boundary comprising a first boundary section, a second        boundary section and a third boundary section which connects the        first and second boundary sections together; and    -   an internal insulating region inside the boundary and configured        to thermally insulate the first boundary section from the second        boundary section;    -   wherein the third boundary section follows an indirect path        between the first and second boundary sections.

The internal insulating region may have a lower pressure than a pressureat the exterior of the boundary.

The first boundary section may be substantially opposite the secondboundary section.

The third boundary section may extend between the first boundary sectionand the second boundary section at an edge of the insulation.

The third boundary section may extend between an edge of the firstboundary section and an edge of the second boundary section.

A thermal conductivity of the third boundary section may be higher thana thermal conductivity of the internal insulating region.

The indirect path may comprise a non-straight path.

The indirect path may comprise a winding path comprising a plurality ofbends.

Sequential ones of the bends may alternate in direction.

The boundary may comprise a wall and the boundary sections may comprisesections of the wall.

The wall may comprise a metallic wall.

Wall sections either side of the internal insulating region may convergeto a sealed gas outlet.

Said wall sections may converge in an end region of the insulation.

A thickness of the insulation may be less than approximately 1 mm.

A thickness of the insulation may be less than approximately 0.1 mm.

A thickness of the insulation may be between approximately 1 mm and0.001 mm.

The wall may have a thickness of at least approximately 100 microns.

A pressure in the internal insulating region may be betweenapproximately 0.1 and approximately 0.001 mbar.

According to the invention, there may be provided an apparatuscomprising a heater configured to heat smokable material to volatilizeat least one component of the smokable material, and the insulationrecited above configured to thermally insulate the apparatus.

The first boundary section may be closer to the heater than the secondboundary section, the second boundary section being separated from theheater by the internal insulating region.

The apparatus may comprise a smokable material heating chamber locatedbetween the heater and the insulation.

The heater may be elongate and may extend along a longitudinal axis of ahousing of the apparatus.

The insulation may be located co-axially around the heater.

The apparatus may be configured to heat the smokable material withoutcombusting the smokable material.

The third boundary section may extend beyond an end of the heater.

According to an aspect of the invention, there is provided an apparatusconfigured to heat smokable material to volatilize at least onecomponent of the smokable material, comprising an infra-red heater.

The infra-red heater may comprise a halogen infra-red heater.

For exemplary purposes only, embodiments of the invention are describedbelow with reference to the accompanying figures in which:

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective, partially cut-away illustration of an apparatusconfigured to heat smokable material to release aromatic compoundsand/or nicotine from the smokable material;

FIG. 2 is a perspective, partially cut-away illustration of an apparatusconfigured to heat smokable material, in which the smokable material isprovided around an elongate ceramic heater divided into radial heatingsections;

FIG. 3 is an exploded, partially cut-away view of an apparatusconfigured to heat smokable material, in which the smokable material isprovided around an elongate ceramic heater divided into radial heatingsections;

FIG. 4 is a perspective, partially cut-away illustration of an apparatusconfigured to heat smokable material, in which the smokable material isprovided around an elongate infra-red heater;

FIG. 5 is an exploded, partially cut-away illustration of an apparatusconfigured to heat smokable material, in which the smokable material isprovided around an elongate infra-red heater;

FIG. 6 is a schematic illustration of part of an apparatus configured toheat smokable material, in which the smokable material is providedaround a plurality of longitudinal, elongate heating sections spacedaround a central longitudinal axis;

FIG. 7 is a perspective illustration of part of an apparatus configuredto heat smokable material, in which the regions of smokable material areprovided between pairs of upstanding heating plates;

FIG. 8 is a perspective illustration of the apparatus shown in FIG. 7,in which an external housing is additionally illustrated;

FIG. 9 is an exploded view of part of an apparatus configured to heatsmokable material, in which the regions of smokable material areprovided between pairs of upstanding heating plates;

FIG. 10 is a flow diagram showing a method of activating heating regionsand opening and closing heating chamber valves during puffing;

FIG. 11 is a schematic illustration of a gaseous flow through anapparatus configured to heat smokable material;

FIG. 12 is a graphical illustration of a heating pattern which can beused to heat smokable material using a heater;

FIG. 13 is a schematic illustration of a smokable material compressorconfigured to compress smokable material during heating;

FIG. 14 is a schematic illustration of a smokable material expanderconfigured to expand smokable material during puffing;

FIG. 15 is a flow diagram showing a method of compressing smokablematerial during heating and expanding the smokable material for puffing;

FIG. 16 is a schematic, cross-sectional illustration of a section ofvacuum insulation configured to insulate heated smokable material fromheat loss;

FIG. 17 is another schematic, cross-sectional illustration of a sectionof vacuum insulation configured to insulate heated smokable materialfrom heat loss;

FIG. 18 is a schematic, cross-sectional illustration of a heat resistivethermal bridge which follows an indirect path from a higher temperatureinsulation wall to a lower temperature insulation wall;

FIG. 19 is a schematic, cross-sectional illustration of a heat shieldand a heat-transparent window which are moveable relative to a body ofsmokable material to selectively allow thermal energy to be transmittedto different sections of the smokable material through the window;

FIG. 20 is schematic, cross sectional illustration of part of anapparatus configured to heat smokable material, in which a heatingchamber is hermetically sealable by check valves;

FIG. 21 is a schematic, cross sectional illustration of an apparatusconfigured to heat smokable material, in which a heater is locatedexternally of a heating chamber and internally of thermal insulation;and

FIG. 22 is a schematic, cross sectional illustration of a partialsection of deep-vacuum insulation configured to thermally insulate anapparatus configured to heat smokable material.

DETAILED DESCRIPTION

As used herein, the term ‘smokable material’ includes any material thatprovides volatilized components upon heating and includes anytobacco-containing material and may, for example, include one or more oftobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco ortobacco substitutes.

An apparatus 1 for heating smokable material comprises an energy source2, a heater 3 and a heating chamber 4. The energy source 2 may comprisea battery such as a Li-ion battery, Ni battery, Alkaline battery and/orthe like, and is electrically coupled to the heater 3 to supplyelectrical energy to the heater 3 when required. The heating chamber 4is configured to receive smokable material 5 so that the smokablematerial 5 can be heated in the heating chamber 4. For example, theheating chamber 4 may be located adjacent to the heater 3 so thatthermal energy from the heater 3 heats the smokable material 5 thereinto volatilize aromatic compounds and nicotine in the smokable material 5without burning the smokable material 5. A mouthpiece 6 is providedthrough which a user of the apparatus 1 can inhale the volatilizedcompounds during use of the apparatus 1. The smokable material 5 maycomprise a tobacco blend.

As shown in FIG. 1, the heater 3 may comprise a substantiallycylindrical, elongate heater 3 and the heating chamber 4 is locatedaround a circumferential, longitudinal surface of the heater 3. Theheating chamber 4 and smokable material 5 therefore comprise co-axiallayers around the heater 3. However, as will be evident from thediscussion below, other shapes and configurations of the heater 3 andheating chamber 4 can alternatively be used.

A housing 7 may contain components of the apparatus 1 such as the energysource 2 and heater 3. As shown in FIG. 1, the housing 7 may comprise anapproximately cylindrical tube with the energy source 2 located towardsits first end 8 and the heater 3 and heating chamber 4 located towardsits opposite, second end 9. The energy source 2 and heater 3 extendalong the longitudinal axis of the housing 7. For example, as shown inFIG. 1, the energy source 2 and heater 3 can be aligned along thecentral longitudinal axis of the housing 7 in an end-to-end arrangementso that an end face of the energy source 2 faces an end face of theheater 3. The length of the housing 7 may be approximately 130 mm, thelength of energy source may be approximately 59 mm, and the length ofthe heater 3 and heating region 4 may be approximately 50 mm. Thediameter of the housing 7 may be between approximately 15 mm andapproximately 18 mm. For example, the diameter of the housing's firstend 8 may be 18 mm whilst the diameter of the mouthpiece 6 at thehousing's second end 9 may be 15 mm. The diameter of the heater 3 may bebetween approximately 2.0 mm and approximately 6.0 mm. The diameter ofthe heater 3 may, for example, be between approximately 4.0 mm andapproximately 4.5 mm or between approximately 2.0 mm and approximately3.0 mm. Heater diameters outside these range may alternatively be used.The depth of the heating chamber 4 may be approximately 5 mm and theheating chamber 4 may have an exterior diameter of approximately 10 mmat its outwardly-facing surface. The diameter of the energy source 2 maybe between approximately 14.0 mm and approximately 15.0 mm, such as 14.6mm.

Heat insulation may be provided between the energy source 2 and theheater 3 to prevent direct transfer of heat from one to the other. Themouthpiece 6 can be located at the second end 9 of the housing 7,adjacent the heating chamber 4 and smokable material 5. The housing 7 issuitable for being gripped by a user during use of the apparatus 1 sothat the user can inhale volatilized smokable material compounds fromthe mouthpiece 6 of the apparatus 1.

Referring to FIGS. 2 and 3, the heater 3 may comprise a ceramics heater3. The ceramics heater 3 may, for example, comprise base ceramics ofalumina and/or silicon nitride which are laminated and sintered.Alternatively, referring to FIGS. 4 and 5, the heater 3 may comprise aninfra-red (IR) heater 3 such as a halogen-IR lamp 3. The IR heater 3 mayhave a low mass and therefore its use can help to reduce the overallmass of the apparatus 1. For example, the mass of the IR heater may be20% to 30% less than the mass of a ceramics heater 3 having anequivalent heating power output. The IR heater 3 also has low thermalinertia and therefore is able to heat the smokable material 5 veryrapidly in response to an activation stimulus. The IR heater 3 may beconfigured to emit IR electromagnetic radiation of between approximately700 nm and 4.5 μm in wavelength.

As indicated above and shown in FIG. 1, the heater 3 may be located in acentral region of the housing 7 and the heating chamber 4 and smokablematerial 5 may be located around the longitudinal surface of the heater3. In this arrangement, thermal energy emitted by the heater 3 travelsin a radial direction outwards from the longitudinal surface of theheater 3 into the heating chamber 4 and the smokable material 5.

The heater 3 may optionally comprise a plurality of individual heatingregions 10. The heating regions 10 may be operable independently of oneanother so that different regions 10 can be activated at different timesto heat the smokable material 5. The heating regions 10 may be arrangedin the heater 3 in any geometric arrangement. However, in the examplesshown in the figures, the heating regions 10 are geometrically arrangedin the heater 3 so that different ones of the heating regions 10 arearranged to predominately and independently heat different regions ofthe smokable material 5.

For example, referring to FIG. 2, the heater 3 may comprise a pluralityof axially aligned heating regions 10. The regions 10 may each comprisean individual element of the heater 3. The heating regions 10 may, forexample, all be aligned with each other along a longitudinal axis of theheater 3, thus providing a plurality of independent heating zones alongthe length of the heater 3. Each heating region 10 may comprise aheating cylinder 10 having a finite length which is significantly lessthan the length of the heater 3 as a whole. The arrangement and featuresof the cylinders 10 are discussed below in terms of heating disks, whereeach disk has a depth which is equivalent to cylinder length. Theheating disks 10 are arranged with their radial surfaces facing oneanother along the length of the heater 3. The radial surfaces of eachdisk 10 may touch the radial surfaces of its neighbouring disks 10.Alternatively, a heat insulating or heat reflecting layer may be presentbetween the radial surfaces of the disks 10 so that thermal energyemitted from each one of the disks 10 does not substantially heat theneighbouring disks 10 and instead travels predominately outwards fromthe circumferential surface of the disk 10 into the heating chamber 4and smokable material 5. Each disk 10 may have substantially the samedimensions as the other disks 10.

In this way, when a particular one of the heating regions 10 isactivated, it supplies thermal energy to the smokable material 5 locatedradially around the heating region 10 without substantially heating theremainder of the smokable material 5.

For example, referring to FIG. 2, the heated region of smokable material5 may comprise a ring of smokable material 5 located around the heatingdisk 10 which has been activated. The smokable material 5 can thereforebe heated in independent sections, for example rings, where each sectioncorresponds to smokable material 5 located directly around a particularone of the heating regions 10 and has a mass and volume which issignificantly less than the body of smokable material 5 as a whole.

Additionally or alternatively, referring to FIG. 6, the heater 3 maycomprise a plurality of elongate, longitudinally extending heatingregions 10 positioned at different locations around the centrallongitudinal axis of the heater 3. Although shown as being of differentlengths in FIG. 6, the longitudinally extending heating regions 10 maybe of substantially the same length so that each extends alongsubstantially the whole length of the heater 3. Each heating region 10may comprise, for example, an individual IR heating element 10 such asan IR heating filament 10. Optionally, a body of heat insulation or heatreflective material may be provided along the central longitudinal axisof the heater 3 so that thermal energy emitted by each heating region 10travels predominately outwards from the heater 3 into the heatingchamber 4 and thus heats the smokable material 5. The distance betweenthe central longitudinal axis of the heater 3 and each of the heatingregions 10 may be substantially equal. The heating regions 10 mayoptionally be contained in a substantially infra-red and/or heattransparent tube, or other housing, which forms a longitudinal surfaceof the heater 3. The heating regions 10 may be fixed in positionrelative to the other heating regions 10 inside the tube.

In this way, when a particular one of the heating regions 10 isactivated, it supplies thermal energy to the smokable material 5 locatedadjacent to the heating region 10 without substantially heating theremainder of the smokable material 5. The heated section of smokablematerial 5 may comprise a longitudinal section of smokable material 5which lies parallel and directly adjacent to the longitudinal heatingregion 10. Therefore, as with the previous example, the smokablematerial 5 can be heated in independent sections.

As will be described further below, the heating regions 10 can each beindividually and selectively activated.

The smokable material 5 may be comprised in a cartridge 11 which can beinserted into the heating chamber 4. For example, as shown in FIG. 1,the cartridge 11 can comprise a smokable material tube 11 which can beinserted around the heater 3 so that the internal surface of thesmokable material tube 11 faces the longitudinal surface of the heater3. The smokable material tube 11 may be hollow. The diameter of thehollow centre of the tube 11 may be substantially equal to, or slightlylarger than, the diameter of the heater 3 so that the tube 11 is a closefit around the heater 3. The length of the cartridge 11 may beapproximately equal to the length of the heater 3 so that the heater 3can heat the cartridge 11 along its whole length.

The housing 7 of the apparatus 1 may comprise an opening through whichthe cartridge 11 can be inserted into the heating chamber 4. The openingmay, for example, comprise a ring-shaped opening located at thehousing's second end 9 so that the cartridge 11 can be slid into theopening and pushed directly into the heating chamber 4. The opening ispreferably closed during use of the apparatus 1 to heat the smokablematerial 5. Alternatively, a section of the housing 7 at the second end9 is removable from the apparatus 1 so that the smokable material 5 canbe inserted into the heating chamber 4. An example of this is shown inFIG. 9. The apparatus 1 may optionally be equipped with a user-operablesmokable material ejection unit, such as an internal mechanismconfigured to slide used smokable material 5 off and/or away from theheater 3. The used smokable material 5 may, for example, be pushed backthrough the opening in the housing 7. A new cartridge 11 can then beinserted as required.

In an alternative configuration of heater 3, the heater 3 comprises aspirally shaped heater 3. The spirally shaped heater 3 may be configuredto screw into the smokable material cartridge 11 and may compriseadjacent, axially-aligned heating regions 10 so as to operate insubstantially the same manner as described the linear, elongate heater 3described above.

In an alternative configuration of heater 3 and heating chamber 4, theheater 3 comprises a substantially elongate tube, which may becylindrical, and the heating chamber 4 is located inside the tube 3rather than around the heater's outside. The heater 3 may comprise aplurality of axially-aligned heating sections, which may each comprise aheating ring configured to heat smokable material 5 located radiallyinwardly from the ring. In this way, the heater 3 is configured toindependently heat separate sections of smokable material 5 in theheating chamber 4 in a manner similar to the heater 3 described above inrelation to FIG. 2. The heat is applied radially inwardly to thesmokable material 5, rather than radially outwardly as previouslydescribed. An example is shown in FIG. 21.

Alternatively, referring to FIGS. 7, 8 and 9, a different geometricalconfiguration of heater 3 and smokable material 5 can be used. Moreparticularly, the heater 3 can comprise a plurality of heating regions10 which extend directly into an elongate heating chamber 4 which isdivided into sections by the heating regions 10. During use, the heatingregions 10 extend directly into an elongate smokable material cartridge11 or other substantially solid body of smokable material 5. Thesmokable material 5 in the heating chamber 4 is thereby divided intodiscrete sections separated from each other by the spaced-apart heatingregions 10. The heater 3, heating chamber 4 and smokable material 5 mayextend together along a central, longitudinal axis of the housing 7. Asshown in FIGS. 7 and 9, the heating regions 10 may each comprise aprojection 10, such as an upstanding heating plate 10, which extendsinto the body of smokable material 5. The projections 10 are discussedbelow in the context of heating plates 10. The principal plane of theheating plates 10 may be substantially perpendicular to the principallongitudinal axis of the body of smokable material 5 and heating chamber4 and/or housing 7. The heating plates 10 may be parallel to oneanother, as shown in FIGS. 7 and 9. Each section of smokable material 5is bounded by a main heating surface of a pair of heating plates 10located either side of the smokable material section, so that activationof one or both of the heating plates 10 will cause thermal energy to betransferred directly into the smokable material 5. The heating surfacesmay be embossed to increase the surface area of the heating plate 10against the smokable material 5. Optionally, each heating plate 10 maycomprise a thermally reflective layer which divides the plate 10 intotwo halves along its principal plane. Each half of the plate 10 can thusconstitute a separate heating region 10 and may be independentlyactivated to heat only the section of smokable material 5 which liesdirectly against that half of the plate 10, rather than the smokablematerial 5 on both sides of the plate 10. Adjacent plates 10, or facingportions thereof, may be activated to heat a section of smokablematerial 5, which is located between the adjacent plates, fromsubstantially opposite sides of the section of smokable material 5.

The elongate smokable material cartridge or body 11 can be installedbetween, and removed from, the heating chamber 4 and heating plates 10by removing a section of the housing 7 at the housing's second end 9, aspreviously described. The heating regions 10 can be individually andselectively activated to heat different sections of the smokablematerial 5 as required.

In this way, when a particular one or pair of the heating regions 10 isactivated, it supplies thermal energy to the smokable material 5 locateddirectly adjacent to the heating region(s) 10 without substantiallyheating the remainder of the smokable material 5. The heated section ofsmokable material 5 may comprise a radial section of smokable material 5located between the heating regions 10, as shown in FIGS. 7 to 9.

The apparatus 1 may comprise a controller 12, such as a microcontroller12, which is configured to control operation of the apparatus 1. Thecontroller 12 is electronically connected to the other components of theapparatus 1 such as the energy source 2 and heater 3 so that it cancontrol their operation by sending and receiving signals. The controller12 is, in particular, configured to control activation of the heater 3to heat the smokable material 5. For example, the controller 12 may beconfigured to activate the heater 3, which may comprise selectivelyactivating one or more heating regions 10, in response to a user drawingon the mouthpiece 6 of the apparatus 1. In this regard, the controller12 may be in communication with a puff sensor 13 via a suitablecommunicative coupling. The puff sensor 13 is configured to detect whena puff occurs at the mouthpiece 6 and, in response, is configured tosend a signal to the controller 12 indicative of the puff. An electronicsignal may be used. The controller 12 may respond to the signal from thepuff sensor 13 by activating the heater 3 and thereby heating thesmokable material 5. The use of a puff sensor 13 to activate the heater3 is not, however, essential and other means for providing a stimulus toactivate the heater 3 can alternatively be used. For example, thecontroller 12 may activate the heater 3 in response to another type ofactivation stimulus such as actuation of a user-operable actuator. Thevolatilized compounds released during heating can then be inhaled by theuser through the mouthpiece 6. The controller 12 can be located at anysuitable position within the housing 7. An example position is betweenthe energy source 2 and the heater 3/heating chamber 4, as illustratedin FIG. 3.

If the heater 3 comprises two or more heating regions 10 as describedabove, the controller 12 may be configured to activate the heatingregions 10 in a predetermined order or pattern. For example, thecontroller 12 may be configured to activate the heating regions 10sequentially along or around the heating chamber 4. Each activation of aheating region 10 may be in response to detection of a puff by the puffsensor 13 or may be triggered in an alternative way, as describedfurther below.

Referring to FIG. 10, an example heating method may comprise a firststep S1 in which an activation stimulus such as a first puff is detectedfollowed by a second step S2 in which a first section of smokablematerial 5 is heated in response to the first puff or other activationstimulus. In a third step S3, hermetically sealable inlet and outletvalves 24 may be opened to allow air to be drawn through the heatingchamber 4 and out of the apparatus 1 through the mouthpiece 6. In afourth step, the valves 24 are closed. These valves 24 are described inmore detail below with respect to FIG. 20. In fifth S5, sixth S6,seventh S7 and eighth S8 steps, a second section of smokable material 5may be heated in response to a second activation stimulus such as asecond puff, with a corresponding opening and closing of the heatingchamber inlet and outlet valves 24. In ninth S9, tenth S10, eleventh S11and twelfth S12 steps, a third section of the smokable material 5 may beheated in response to a third activation stimulus such as a third puffwith a corresponding opening and closing of the heating chamber inletand outlet valves 24, and so on. As referred to above, means other thana puff sensor 13 could alternatively be used. For example, a user of theapparatus 1 may actuate a control switch to indicate that he/she istaking a new puff. In this way, a fresh section of smokable material 5may be heated to volatilize nicotine and aromatic compounds for each newpuff. The number of heating regions 10 and/or independently heatablesections of smokable material 5 may correspond to the number of puffsfor which the cartridge 11 is intended to be used. Alternatively, eachindependently heatable smokable material section 5 may be heated by itscorresponding heating region(s) 10 for a plurality of puffs such as two,three or four puffs, so that a fresh section of smokable material 5 isheated only after a plurality of puffs have been taken whilst heatingthe previous smokable material section.

Instead of activating each heating region 10 in response to anindividual puff, the heating regions 10 may alternatively be activatedsequentially, one after the other, in response to a single, initial puffat the mouthpiece 6. For example, the heating regions 10 may beactivated at regular, predetermined intervals over the expectedinhalation period for a particular smokable material cartridge 11. Theinhalation period may, for example, be between approximately one andapproximately four minutes. Therefore, at least the fifth and ninthsteps S5, S9 shown in FIG. 10 are optional. Each heating region 10 maybe activated for a predetermined period corresponding to the duration ofthe single or plurality of puffs for which the correspondingindependently heatable smokable material section 5 is intended to beheated. Once all of the heating regions 10 have been activated for aparticular cartridge 11, the controller 12 may be configured to indicateto the user that the cartridge 11 should be changed. The controller 12may, for example, activate an indicator light at the external surface ofthe housing 7.

It will be appreciated that activating individual heating regions 10 inorder rather than activating the entire heater 3 means that the energyrequired to heat the smokable material 5 is reduced over what would berequired if the heater 3 were activated fully over the entire inhalationperiod of a cartridge 11. Therefore, the maximum required power outputof the energy source 2 is also reduced. This means that a smaller andlighter energy source 2 can be installed in the apparatus 1.

The controller 12 may be configured to de-activate the heater 3, orreduce the power being supplied to the heater 3, in between puffs. Thissaves energy and extends the life of the energy source 2. For example,upon the apparatus 1 being switched on by a user or in response to someother stimulus, such as detection of a user placing their mouth againstthe mouthpiece 6, the controller 12 may be configured to cause theheater 3, or next heating region 10 to be used to heat the smokablematerial 5, to be partially activated so that it heats up in preparationto volatilize components of the smokable material 5. The partialactivation does not heat the smokable material 5 to a sufficienttemperature to volatilize nicotine. A suitable temperature could bebelow 120° C., such as 100° C. or below. An example is a temperaturebetween 60° C. and 100° C., such as a temperature between 80° C. and100° C. The temperature may be less than 100° C. In response todetection of a puff by the puff sensor 13, the controller 12 can thencause the heater 3 or heating region 10 in question to heat the smokablematerial 5 further in order to rapidly volatilize the nicotine and otheraromatic compounds for inhalation by the user. If the smokable material5 comprises tobacco, a suitable temperature for volatilizing thenicotine and other aromatic compounds may be 100° C. or above, such as120° C. or above. An example is a temperature between 100° C. and 250°C., such as between 150° C. and 250° C. or between 130° C. and 180° C.The temperature may be more than 100° C. An example full activationtemperature is 150° C., although other values such as 250° C. are alsopossible. A super-capacitor can optionally be used to provide the peakcurrent used to heat the smokable material 5 to the volatizationtemperature. An example of a suitable heating pattern is shown in FIG.12, in which the peaks may respectively represent the full activation ofdifferent heating regions 10. As can be seen, the smokable material 5 ismaintained at the volatization temperature for the approximate period ofthe puff which, in this example, is two seconds.

Three example operational modes of the heater 3 are described below.

In a first operational mode, during full activation of a particularheating region 10, all other heating regions 10 of the heater aredeactivated. Therefore, when a new heating region 10 is activated, theprevious heating region is deactivated. Power is supplied only to theactivated region 10.

Alternatively, in a second operational mode, during full activation of aparticular heating region 10, one or more of the other heating regions10 may be partially activated. Partial activation of the one or moreother heating regions 10 may comprise heating the other heatingregion(s) 10 to a temperature which is sufficient to substantiallyprevent condensation of components such as nicotine volatized from thesmokable material 5 in the heating chamber 4. The temperature of theheating regions 10 which are partially activated is less than thetemperature of the heating region 10 which is fully activated. Thesmokable material 10 located adjacent the partially activated regions 10is not heated to a temperature sufficient to volatize components of thesmokable material 5.

Alternatively, in a third operational mode, once a particular heatingregion 10 has been activated, it remains fully activated until theheater 3 is switched off. Therefore, the power supplied to the heater 3incrementally increases as more of the heating regions 10 are activatedduring inhalation from the cartridge 11. As with the second modepreviously described, the continuing activation of the heating regions10 substantially prevent condensation of components such as nicotinevolatized from the smokable material 5 in the heating chamber 4.

The apparatus 1 may comprise a heat shield 3 a, which is located betweenthe heater 3 and the heating chamber 4/smokable material 5. The heatshield 3 a is configured to substantially prevent thermal energy fromflowing through the heat shield 3 a and therefore can be used toselectively prevent the smokable material 5 from being heated even whenthe heater 3 is activated and emitting thermal energy. Referring to FIG.19, the heat shield 3 a may, for example, comprise a cylindrical layerof heat reflective material which is located co-axially around theheater 3. Alternatively, if the heater 3 is located around the heatingchamber 4 and smokable material 5 as previously described, the heatshield 3 a may comprise a cylindrical layer of heat reflective materialwhich is located co-axially around the heating chamber 4 and co-axiallyinside of the heater 3. The heat shield 3 a may additionally oralternatively comprise a heat-insulating layer configured to insulatethe heater 3 from the smokable material 5. The heat shield 3 a comprisesa substantially heat-transparent window 3 b which allows thermal energyto propagate through the window 3 b and into the heating chamber 4 andsmokable material 5. Therefore, the section of smokable material 5 whichis aligned with the window 3 b is heated whilst the remainder of thesmokable material 5 is not. The heat shield 3 a and window 3 b may berotatable or otherwise moveable with respect to the smokable material 5so that different sections of the smokable material 5 can be selectivelyand individually heated by rotating or moving the heat shield 3 a andwindow 3 b. The effect is similar to the effect provided by selectivelyand individually activating the heating regions 10 referred to above.For example, the heat shield 3 a and window 3 b may be rotated orotherwise moved incrementally in response to a signal from the puffdetector 13. Additionally or alternatively, the heat shield 3 a andwindow 3 b may be rotated or otherwise moved incrementally in responseto a predetermined heating period having elapsed. Movement or rotationof the heat shield 3 a and window 3 b may be controlled by electronicsignals from the controller 12. The relative rotation or other movementof the heat shield 3 a/window 3 b and smokable material 5 may be drivenby a stepper motor 3 c under the control of the controller 12. This isillustrated in FIG. 19. Alternatively, the heat shield 3 a and window 3b may be manually rotated using a user control such as an actuator onthe housing 7. The heat shield 3 a does not need to be cylindrical andmay comprise optionally comprise one or more suitably positionedlongitudinally extending elements and or/plates.

It will be appreciated that a similar result can be obtained by rotatingor moving the smokable material 5 relative to the heater 3, heat shield3 a and window 3 b. For example, the heating chamber 4 may be rotatablearound the heater 3. If this is the case, the above description relatingto movement of the heat shield 3 a can be applied instead to movement ofthe heating chamber 4 relative to the heat shield 3 a.

The heat shield 3 a may comprise a coating on the longitudinal surfaceof the heater 3. In this case, an area of the heater's surface is leftuncoated to form the heat-transparent window 3 b. The heater 3 can berotated or otherwise moved, for example under the control of thecontroller 12 or user controls, to cause different sections of thesmokable material 5 to be heated. Alternatively, the heat shield 3 a andwindow 3 b may comprise a separate shield 3 a which is rotatable orotherwise moveable relative to both the heater 3 and the smokablematerial 5 under the control of the controller 12 or other usercontrols.

Referring to FIG. 6, the apparatus 1 may comprise air inlets 14 whichallow external air to be drawn into the housing 7 and through the heatedsmokable material 5 during puffing. The air inlets 14 may compriseapertures 14 in the housing 7 and may be located upstream from thesmokable material 5 and heating chamber 4 towards the first end 8 of thehousing 7. This is shown in FIG. 1. Another example is shown in FIG. 11.Air drawn in through the inlets 14 travels through the heated smokablematerial 5 and therein is enriched with smokable material vapours, suchas aroma vapours, before being inhaled by the user at the mouthpiece 6.Optionally, as shown in FIG. 11, the apparatus 1 may comprise a heatexchanger 15 configured to warm the air before it enters the smokablematerial 5 and/or to cool the air before it is drawn through themouthpiece 6. For example, the heat exchanger 15 may be configured touse heat extracted from the air entering the mouthpiece 6 to warm newair before it enters the smokable material 5.

The apparatus 1 may comprise a smokable material compressor 16configured to cause the smokable material 5 to compress upon activationof the compressor 16. The apparatus 1 can also comprise a smokablematerial expander 17 configured to cause the smokable material 5 toexpand upon activation of the expander 17. The compressor 16 andexpander 17 may, in practice, be implemented as the same unit as will beexplained below. The smokable material compressor 16 and expander 17 mayoptionally operate under the control of the controller 12. In this case,the controller 12 is configured to send a signal, such as an electricalsignal, to the compressor 16 or expander 17 which causes the compressor16 or expander 17 to respectively compress or expand the smokablematerial 5. Alternatively, the compressor 16 and expander 17 may beactuated by a user of the apparatus 1 using a manual control on thehousing 7 to compress or expand the smokable material 5 as required.

The compressor 16 is principally configured to compress the smokablematerial 5 and thereby increase its density during heating. Compressionof the smokable material increases the thermal conductivity of the bodyof smokable material 5 and therefore provides a more rapid heating andconsequent rapid volatization of nicotine and other aromatic compounds.This is preferable because it allows the nicotine and aromatics to beinhaled by the user without substantial delay in response to detectionof a puff. Therefore, the controller 12 may activate the compressor 16to compress the smokable material 5 for predetermined heating period,for example one second, in response to detection of a puff. Thecompressor 16 may be configured to reduce its compression of thesmokable material 5, for example under the control of the controller 12,after the predetermined heating period. Alternatively, the compressionmay be reduced or automatically ended in response to the smokablematerial 5 reaching a predetermined threshold temperature. A suitablethreshold temperature may be in the range of approximately 100° C. to250° C., such as between 100° C. and 220° C., between 150° C. and 250°C., between 100° C. and 200° C. or between 130° C. and 180° C. Thethreshold temperature may be above 100° C., such as a value above 120°C., and may be user selectable. A temperature sensor may be used todetect the temperature of the smokable material 5.

The expander 17 is principally configured to expand the smokablematerial 5 and thereby decrease its density during puffing. Thearrangement of smokable material 5 in the heating chamber 4 becomes moreloose when the smokable material 5 has been expanded and this aids thegaseous flow, for example air from the inlets 14, through the smokablematerial 5. The air is therefore more able to carry the volatilizednicotine and aromatics to the mouthpiece 6 for inhalation. Thecontroller 12 may activate the expander 17 to expand the smokablematerial 5 immediately following the compression period referred toabove so that air can be drawn more freely through the smokable material5. Actuation of the expander 17 may be accompanied by a user-audiblesound or other indication to indicate to the user that the smokablematerial 5 has been heated and that puffing can commence.

Referring to FIGS. 13 and 14, the compressor 16 and expander 17 maycomprise a spring-actuated driving rod which is configured to compressthe smokable material 5 in the heating chamber 4 when the spring isreleased from compression. This is schematically illustrated in FIGS. 13and 14, although it will be appreciated that other implementations couldbe used. For example, the compressor 16 may comprise a ring, having athickness approximately equal to the tubular-shaped heating chamber 4described above, which is driven by a spring or other means into theheating chamber 4 to compress the smokable material 5. Alternatively,the compressor 16 may be comprised as part of the heater 3 so that theheater 3 itself is configured to compress and expand the smokablematerial 5 under the control of the controller 12. For example, wherethe heater 3 comprises upstanding heating plates 10 of the typepreviously described, the plates 10 may be independently moveable in alongitudinal direction of the heater 3 to expand or compress thesections of smokable material 5 which are located adjacent to them. Amethod of compressing and expanding the smokable material 5 is shown inFIG. 15.

Thermal insulation 18 may be provided between the smokable material 5and an external surface 19 of the housing 7 to reduce heat loss from theapparatus 1 and therefore improve the efficiency with which the smokablematerial 5 is heated. For example, referring to FIG. 1, a wall of thehousing 7 may comprise a layer of insulation 18 which extends around theoutside of the heating chamber 4. The insulation layer 18 may comprise asubstantially tubular length of insulation 18 located co-axially aroundthe heating chamber 4 and smokable material 5. This is shown in FIG. 1.Another example is shown in FIG. 21. It will be appreciated that theinsulation 18 could also be comprised as part of the smokable materialcartridge 11, in which it would be located co-axially around the outsideof the smokable material 5.

Referring to FIG. 16, the insulation 18 may comprise vacuum insulation18. For example, the insulation 18 may comprise a layer which is boundedby a wall material 19 such as a metallic material. An internal region orcore 20 of the insulation 18 may comprise an open-cell porous material,for example comprising polymers, aerogels or other suitable material,which is evacuated to a low pressure. The pressure in the internalregion 20 may be in the range of 0.1 to 0.001 mbar. The wall 19 of theinsulation 18 is sufficiently strong to withstand the force exertedagainst it due to the pressure differential between the core 20 andexternal surfaces of the wall 19, thereby preventing the insulation 18from collapsing. The wall 19 may, for example, comprise a stainlesssteel wall 19 having a thickness of approximately 100 μm. The thermalconductivity of the insulation 18 may be in the range of 0.004 to 0.005W/m/K. The heat transfer coefficient of the insulation 18 may be betweenapproximately 1.10 W/(m²K) and approximately 1.40 W/(m²K) within atemperature range of between 100 degrees Celsius and 250 degreesCelsius, such as between approximately 150 degrees Celsius andapproximately 250 degrees Celsius. The gaseous conductivity of theinsulation 18 is negligible. A reflective coating may be applied to theinternal surfaces of the wall material 19 to minimize heat losses due toradiation propagating through the insulation 18. The coating may, forexample, comprise an aluminium IR reflective coating having a thicknessof between approximately 0.3 μm and 1.0 μm. The evacuated state of theinternal core region 20 means that the insulation 18 functions even whenthe thickness of the core region 20 is very small. The insulatingproperties are substantially unaffected by its thickness. This helps toreduce the overall size of the apparatus 1.

As shown in FIG. 16, the wall 19 may comprise an inwardly-facing section21 and an outwardly-facing section 22. The inwardly-facing section 21substantially faces the smokable material 5 and heating chamber 4. Theoutwardly-facing section 22 substantially faces the exterior of thehousing 7. During operation of the apparatus 1, the inwardly-facingsection 21 may be warmer due to the thermal energy originating from theheater 3, whilst the outwardly-facing section 22 is cooler due to theeffect of the insulation 18. The inwardly-facing section 21 and theoutwardly-facing section 22 may, for example, comprise substantiallyparallel longitudinally-extending walls 19 which are at least as long asthe heater 3. The internal surface of the outwardly-facing wall section22, i.e. the surface facing the evacuated core region 20, may comprise acoating for absorbing gas in the core 20. A suitable coating is atitanium oxide film.

The thermal insulation 18 may comprise hyper-deep vacuum insulation suchas an Insulon® Shaped-Vacuum Thermal Barrier as described in U.S. Pat.No. 7,374,063. The overall thickness of such insulation 18 may beextremely small. An example thickness is between approximately 1 mm andapproximately 1 μm, such as approximately 0.1 mm, although other largeror smaller thicknesses are also possible. The thermally insulatingproperties of the insulation 18 are substantially unaffected by itsthickness and therefore thin insulation 18 can be used without anysubstantial additional heat loss from the apparatus 1. The very smallthickness of the thermal insulation 18 may allow the size of the housing7 and apparatus 1 as a whole to be reduced beyond the sizes previouslydiscussed and may allow the thickness, for example the diameter, of theapparatus 1 to be approximately equal to smoking articles such ascigarettes, cigars and cigarillos. The weight of the apparatus 1 mayalso be reduced, providing similar benefits to the size reductionsdiscussed above.

Although the thermal insulation 18 described previously may comprise agas-absorbing material to maintain or aid with creation of the vacuum inthe core region 20, a gas absorbing material is not used in thedeep-vacuum insulation 18. The absence of the gas absorbing materialaids with keeping the thickness of the insulation 18 very low and thushelps to reduce the overall size of the apparatus 1.

The geometry of the hyper-deep insulation 18 allows the vacuum in theinsulation to be deeper than the vacuum used to extract molecules fromthe core region 20 of the insulation 18 during manufacture. For example,the deep vacuum inside the insulation 18 may be deeper than that of thevacuum-furnace chamber in which it is created. The vacuum inside theinsulation 18 may, for example, be of the order 10⁻⁷ Torr. Referring toFIG. 22, an end of the core region 20 of the deep-vacuum insulation 18may taper as the outwardly facing section 22 and inwardly facing section21 converge to an outlet 25 through which gas in the core region 20 maybe evacuated to create a deep vacuum during manufacture of theinsulation 18. FIG. 22 illustrates the outwardly facing section 22converging towards the inwardly facing section 21 but a conversearrangement, in which the inwardly facing section 21 converges to theoutwardly facing section 22, could alternatively be used. The convergingend of the insulating wall 19 is configured to guide gas molecules inthe core region 20 out of the outlet 25 and thereby create a deep vacuumin the core 20. The outlet 25 is sealable so as to maintain a deepvacuum in the core region 20 after the region 20 has been evacuated. Theoutlet 25 can be sealed, for example, by creating a brazed seal at theoutlet 25 by heating brazing material at the outlet 25 after gas hasbeen evacuated from the core 20. Alternative sealing techniques could beused.

In order to evacuate the core region 20, the insulation 18 may be placedin a low pressure, substantially evacuated environment such as a vacuumfurnace chamber so that gas molecules in the core region 20 flow intothe low pressure environment outside the insulation 18. When thepressure inside the core region 20 becomes low, the tapered geometry ofthe core region 20, and in particular the converging sections 21, 22referred to above, becomes influential in guiding remaining gasmolecules out the core 20 via the outlet 25. Specifically, when the gaspressure in the core region 20 is low, the guiding effect of theconverging inwardly and outwardly facing sections 21, 22 is effective tochannel the remaining gas molecules inside the core 20 towards theoutlet 25 and make the probability of gas exiting the core 20 higherthan the probability of gas entering the core 20 from the external, lowpressure environment. In this way, the geometry of the core 20 allowsthe pressure inside the core 20 to be reduced below the pressure of theenvironment outside the insulation 18.

Optionally, as previously described, one or more low emissivity coatingsmay be present on the internal surfaces of the inwardly and outwardlyfacing sections 21, 22 of the wall 19 in order to substantially preventheat losses by radiation.

Although the shape of the insulation 18 is generally described herein assubstantially cylindrical or similar, the thermal insulation 18 could beanother shape, for example in order to accommodate and insulate adifferent configuration of the apparatus 1 such as different shapes andsizes of heating chamber 4, heater 3, housing 7 or energy source 2. Forexample, the size and shape of deep-vacuum insulation 18 such as anInsulon® Shaped-Vacuum Thermal Barrier referred to above issubstantially unlimited by its manufacturing process. Suitable materialsfor forming the converging structure described above include ceramics,metals, metalloids and combinations of these.

Referring to the schematic illustration in FIG. 17, a thermal bridge 23may connect the inwardly-facing wall section 21 to the outwardly-facingwall section 22 at one or more edges of the insulation 18 in order tocompletely encompass and contain the low pressure core 20. The thermalbridge 23 may comprise a wall 19 formed of the same material as theinwardly and outwardly-facing sections 21, 22. A suitable material isstainless steel, as previously discussed. The thermal bridge 23 has agreater thermal conductivity than the insulating core 20 and thereforemay undesirably conduct heat out of the apparatus 1 and, in doing so,reduce the efficiency with which the smokable material 5 is heated.

To reduce heat losses due to the thermal bridge 23, the thermal bridge23 may be extended to increase its resistance to heat flow from theinwardly-facing section 21 to the outwardly-facing section 22. This isschematically illustrated in FIG. 18. For example, the thermal bridge 23may follow an indirect path between the inwardly-facing section 21 ofwall 19 and the outwardly-facing section 22 of wall 19. This may befacilitated by providing the insulation 18 over a longitudinal distancewhich is longer than the lengths of the heater 3, heating chamber 4 andsmokable material 5 so that the thermal bridge 23 can gradually extendfrom the inwardly-facing section 21 to the outwardly-facing section 22along the indirect path, thereby reducing the thickness of the core 20to zero, at a longitudinal location in the housing 7 where the heater 3,heating chamber 4 and smokable material 5 are not present.

Referring to FIG. 20, as previously discussed, the heating chamber 4insulated by the insulation 18 may comprise inlet and outlet valves 24which hermetically seal the heating chamber 4 when closed. The valves 24can thereby prevent air from undesirably entering and exiting thechamber 4 and can prevent smokable material flavours from exiting thechamber 4. The inlet and outlet values 24 may, for example, be providedin the insulation 18. For example, between puffs, the valves 24 may beclosed by the controller 12 so that all volatilized substances remaincontained inside the chamber 4 in-between puffs. The partial pressure ofthe volatized substances between puffs reaches the saturated vapourpressure and the amount of evaporated substances therefore depends onlyon the temperature in the heating chamber 4. This helps to ensure thatthe delivery of volatilized nicotine and aromatic compounds remainsconstant from puff to puff. During puffing, the controller 12 isconfigured to open the valves 24 so that air can flow through thechamber 4 to carry volatilized smokable material components to themouthpiece 6. A membrane can be located in the valves 24 to ensure thatno oxygen enters the chamber 4. The valves 24 may be breath-actuated sothat the valves 24 open in response to detection of a puff at themouthpiece 6. The valves 24 may close in response to a detection that apuff has ended. Alternatively, the valves 24 may close following theelapse of a predetermined period after their opening. The predeterminedperiod may be timed by the controller 12. Optionally, a mechanical orother suitable opening/closing means may be present so that the valves24 open and close automatically. For example, the gaseous movementcaused by a user puffing on the mouthpiece 6 may be used to open andclose the valves 24. Therefore, the use of the controller 12 is notnecessarily required to actuate the valves 24.

The mass of the smokable material 5 which is heated by the heater 3, forexample by each heating region 10, may be in the range of 0.2 to 1.0 g.The temperature to which the smokable material 5 is heated may be usercontrollable, for example to any temperature within the temperaturerange of 100° C. to 250° C., such as any temperature within the range of150° C. to 250° C. or the other volatizing temperature ranges previouslydescribed. The mass of the apparatus 1 as a whole may be in the range of70 to 125 g. A battery 2 with a capacity of 1000 to 3000 mAh and voltageof 3.7V can be used. The heating regions 10 may be configured toindividually and selectively heat between approximately 10 and 40sections of smokable material 5 for a single cartridge 11.

It will be appreciated that any of the alternatives described above canbe used singly or in combination. For example, as discussed above, theheater 3 may be located around the outside of the smokable material 5rather than the smokable material 5 being located around the heater 3.The heater 3 may therefore circumscribe the smokable material 5 to applyheat to the smokable material 5 in a substantially radially inwarddirection.

In order to address various issues and advance the art, the entirety ofthis disclosure shows by way of illustration various embodiments inwhich the claimed invention(s) may be practiced and provide for superiorapparatus. The advantages and features of the disclosure are of arepresentative sample of embodiments only, and are not exhaustive and/orexclusive. They are presented only to assist in understanding and teachthe claimed features. It is to be understood that advantages,embodiments, examples, functions, features, structures, and/or otheraspects of the disclosure are not to be considered limitations on thedisclosure as defined by the claims or limitations on equivalents to theclaims, and that other embodiments may be utilised and modifications maybe made without departing from the scope and/or spirit of thedisclosure. Various embodiments may suitably comprise, consist of, orconsist essentially of, various combinations of the disclosed elements,components, features, parts, steps, means, etc. In addition, thedisclosure includes other inventions not presently claimed, but whichmay be claimed in future.

1. Thermal insulation comprising: a boundary comprising a first boundarysection, a second boundary section and a third boundary section whichconnects the first and second boundary sections together; and aninternal insulating region inside the boundary and configured tothermally insulate the first boundary section from the second boundarysection; wherein the third boundary section follows an indirect pathbetween the first and second boundary sections.
 2. Insulation accordingto claim 1, wherein the internal insulating region has a lower pressurethan a pressure at the exterior of the boundary.
 3. Insulation accordingto claim 1 or 2, wherein the first boundary section is substantiallyopposite the second boundary section.
 4. Insulation according to anypreceding claim, wherein the third boundary section extends between thefirst boundary section and the second boundary section at an edge of theinsulation.
 5. Insulation according to any preceding claim, wherein thethird boundary section extends between an edge of the first boundarysection and an edge of the second boundary section.
 6. Insulationaccording to any preceding claim, wherein a thermal conductivity of thethird boundary section is higher than a thermal conductivity of theinternal insulating region.
 7. Insulation according to any precedingclaim, wherein the indirect path comprises a non-straight path. 8.Insulation according to any preceding claim, wherein the indirect pathcomprises a winding path comprising a plurality of bends.
 9. Insulationaccording to claim 8, wherein sequential ones of the bends alternate indirection.
 10. Insulation according to any preceding claim, wherein theboundary comprises a wall and the boundary sections comprise sections ofthe wall.
 11. Insulation according to claim 10, wherein the wallcomprises a metallic wall.
 12. Insulation according to claim 10 or 11,wherein the wall has a thickness of at least approximately 100 microns.13. Insulation according to any of claims 1 to 12, where the internalinsulating region comprises a deep vacuum.
 14. Insulation according toclaim 13, wherein the vacuum is a hyper deep vacuum.
 15. An apparatusaccording to any preceding claim, wherein a pressure in the internalinsulating region is of the order 10⁻⁷ Torr.
 16. Insulation according toany of claims 1 to 12, wherein a pressure in the internal insulatingregion is between approximately 0.1 and approximately 0.001 mbar.
 17. Anapparatus according to any preceding claim, wherein a thickness of theinsulation is less than approximately 1 mm.
 18. An apparatus accordingto any preceding claim, wherein a thickness of the insulation is lessthan approximately 0.1 mm.
 19. An apparatus according to any of claims 1to 16, wherein a thickness of the insulation is between approximately 1mm and 0.001 mm.
 20. An apparatus comprising a heater configured to heatsmokable material to volatilize at least one component of the smokablematerial, and insulation according to any of claims 1 to 18 configuredto thermally insulate the apparatus.
 21. An apparatus according to claim20, wherein the first boundary section is closer to the heater than thesecond boundary section, the second boundary section being separatedfrom the heater by the internal insulating region.
 22. An apparatusaccording to claim 20 or 21, comprising a smokable material heatingchamber located between the heater and the insulation.
 23. An apparatusaccording to any of claims 20 to 22, wherein the heater is elongate andextends along a longitudinal axis of a housing of the apparatus.
 24. Anapparatus according to any of claims 20 to 23, wherein the insulation islocated co-axially around the heater.
 25. An apparatus according to anyof claims 20 to 24, wherein the apparatus is configured to heat thesmokable material without combusting the smokable material.
 26. Anapparatus according to any of claims 20 to 25, wherein the thirdboundary section extends beyond an end of the heater.